auth.pytest_plugin: Adjust error type according to reality
Prior to this commit, this raised a basic error message instead of a json dict bytes encoded [1]
This commit fixes it.
The reality of tests trying to fix the deposit authentication handling which is awkward for now.
Related to swh-deposit#2858 (closed) Related to swh-deposit!226 (closed)
- [1] Related to swh/meta$978
Test Plan
tox
Migrated from D5304 (view on Phabricator)